Results of behavioral and audiological tests with humans imply that ability to understand speech and other complex signals (particularly in a noisy listening situation) suffers loss from noise insult in excess of what could be inferred from pure tone thresholds measured in the quiet. These findings suggest that a complex interaction between the various levels of the auditory nervous system and between the auditory nervous system and functionally different receptors of the auditory end organ play a vital role in "sharpening" the sensory process. Until recently it has not been possible to study the effect of noise insult on rapidly changing speech or speech-like signals because such study necessitated that use of extremely fast-acting signal analysis (frequency domain) equipment coupled with the memory capacity of a minicomputer. The PDP 1140 Minicomputer in our lab is being interfaced with signal analysis equipment for processing electrophysiological data by Fast Fourier Transformation, Auto and Cross Correlation analysis. The responses from both multi cochlear microphonic (CM) and responses from individual nerve fibers of noise exposed and non-noise exposed animals will be obtained.